1. Field
The present invention relates to a light-emitting diode (LED) lamp, and more particularly, to an LED lamp which can realize light distribution characteristics similar to those of an incandescent lamp by radiating light not only forwards but also sideways and backwards and effectively dissipate heat that is generated through the light emission of an LED.
2. Discussion of the Background
Recently, light-emitting diodes (LEDs) are being used as light sources in a variety of fields due to their variety of characteristics, including high efficiency, clearness or the like. Among them, in the illumination field, conventional lamps are being rapidly replaced with LED lamps to which LEDs are applied.
LEDs used as light sources in such LED lamps have an orientation angle of 120°. Conventionally, the characteristics of the orientation angle were not regarded as a significant issue although light efficiency, longevity or the like was regarded important when LEDs were applied to lamps.
Recently, however, demands for LED lamps of which an orientation angle and light distribution characteristics are similar to those of existing incandescent lamps are increasing.
In response to such demands, several types of LED lamps, such as a lens type, a reflector type and a vertical LED type, were developed in order to realize the orientation angle and light distribution characteristic similar to those of conventional incandescent lamps.
The reflector type LED lamp can efficiently send light to the rear of an LED, i.e. a light source. However, light efficiency is low, which is problematic. In addition, although the lens type LED lamp is more effective than the reflector type LED lamp in terms of light control and light efficiency, there is a technical problem in that it is difficult to realize a light orientation characteristic. In particular, it is very difficult to send light to the rear side of LEDs, which is problematic.
In addition, in the vertical LED type lamp, the upper portions of LEDs are disposed perpendicular to a bulb such that light is emitted sideways. This consequently leads to a satisfactory light distribution curve. However, it is difficult to control the LEDs to uniformly radiate light in all directions. Furthermore, since substrates on which LEDs are mounted must be divided, mounting works are difficult and the cost is increased, which are problematic.
Meanwhile, LEDs has a problem in that they generate a large amount of heat while emitting light. In order to use such LEDs for illumination, not only an improvement in the quality of light emission but also high-power light emission of several thousand lumens is required. Since this high-powered light emission is proportional to an input current, an intended level of light power can be realized when a large current is provided. However, an increase in the input current leads to an increased amount of heat, which is problematic.
Therefore, an approach that can overcome the lower performance and reliability of LEDs due to the heat while producing high-powered light is required. The heat generated from LEDs lowers the efficiency of the operation of LEDs and distorts the color of light by deteriorating a fluorescent material that is used for converting the wavelength of light, which are problematic. Furthermore, heat generated from LEDs can have an adverse effect on the operation of other electronic components disposed around LEDs.
Accordingly, as for LED lamps, it is becoming more important to develop a heat dissipation structure that can effectively dissipate heat generated from LEDs, and thus a variety of research and development is underway.